1. Field of the Invention
The invention relates to a light emitting diode package and method for fabricating the same, and more particularly to a multi-chip light emitting diode package and method for fabricating the same.
2. Description of the Related Art
Light emitting diodes (LEDs) have high brightness, low volume, low power consumption and long operating lifespan and such as, are used in a variety of display products. The luminescent principle of LEDs is as follows. A voltage is applied to a diode to drive an electron and a hole combination. The combination releases light from the diode.
Multi-chip light emitting diodes are generally divided into two-chip light emitting diode and three-chip light emitting diode packages. Using the three-chip light emitting diode as an example, the diode is applied with a driver circuit to radiate a single irradiation or mix all irradiations emitted by individual chips.
In general, the light emitting angle of a multi-chip light emitting diode is determined according to requirement. U.S. Pat. No. 5,266,817 discloses a method for adjusting the light emitting angle of chips on a lead frame. A scattering layer is formed on the bottom and sidewall of a lead frame, and the light emitting angles of the all three chips are adjusted at the same time. However, it is difficult to simultaneously achieve the objective light emitting angle of individual chips via the scattering layer, since the wavelength and location of the three chips may be different.
JP Patent 2001210874 discloses a single-chip light emitting diode package employing a scattering layer, comprising a mixture of resin and fluorescent compounds, covering the surface of the chip. The thickness of the scattering layer, however, is not uniform.
TW patent 595018 discloses single-chip light emitting diode package employing two phosphorescent material layers with different phosphorescent concentrations as a scattering layer, filling into a cavity of a lead frame. The aforementioned prior arts relate to single-chip light emitting diode packages. Note that it is difficult to ensure equal scattering material ratio for per unit resin volume, since the scattering material is mixed with and encapsuled by the resin for a conventional scattering layer. Therefore, the light emitting angle cannot be precisely adjusted by the conventional scattering layer. If the conventional scattering layer is applied in a multi-chip light emitting diode package, each chip of the multi-chip light emitting diode package would not simultaneously achieve the objective light emitting angles since the conventional scattering layer cannot adjust the light emitting angle of each chip individually.
Therefore, it is desirable to devise a novel light emitting diode package that improves upon the aforementioned problems.